You know, I didn't even realize this, but the game has dynamic battle music. Sure, sure, it'll switch to the boss theme if a unique monster aggros while you're fighting something else, but that's not the only time it changes. While this is fairly early in the game, I'll go ahead and spoiler mark it anyway.
Also, don't look at the suggested video titles. They're kind of spoilery, too.
If I link to this music and do my best Shulk impression "The future... it's changing! ... Not gonna happen!" This is the vision comeback music. You've heard it so many times already, but if I hadn't just told you it was special event music and not just part of the boss themes, would you have noticed?